An air filter assembly including abutting, cylindrical housing halves, with toothed outer ends, joined via spaced, T-shaped appendages; a cylindrical air inlet of abutting semi-cylindrical housing inlet portions; a primary filter pack, for slip-fit insertion into either housing half, having an end cap integral with a cylindrical primary filter pack having sealing material on its inner end; a filter outlet end with a toothed peripheral portion, for slip-fit insertion into and angular adjustment relative to either housing end, and a plurality of ribs defining locating surfaces for an air outlet portion, and main and safety filters; the latter having a truncated cone body and an inverted conical portion; and a filter attachment base having curved bed portions, for receiving a housing periphery portion, including spaced support pads and slot portions for angularly adjustably receiving like numbers of T-shaped appendages, with a locking mechanism joining the housing and attachment base.